A resonator that can be excited by an electrical signal is indeed an electrical or electromechanical device defined primarily by its resonance frequency f0 and its quality factor Q associated with the energy losses of the resonator. The resonance frequency and the quality factor depend on the geometrical parameters and on the nature of the materials used in the case of an electromechanical resonator, or on the values of its R, L or C type components in the case of an electrical resonator. Such a resonator can therefore be used in open loop mode to provide bandpass filtering about its resonance frequency, the bandwidth being all the narrower as the quality factor increases. It can also be used in closed loop mode, using an electronic feedback circuit to handle its oscillation by generating, from the signal supplied by the resonator, a signal capable of exciting the resonator on its resonance frequency f0.
An array of coupled resonators is made up of several resonators that are coupled together mechanically (in the case of electromechanical resonators) or electrically (in the case of electrical resonators) so that the excitation of one of them provokes the mechanical vibration or electrical oscillation of all of the coupled resonators that have at least a degree of freedom in this array. These arrays of coupled resonators make it possible to envisage signal processing functions offering better power and better performance than when just one resonator is used. For example, when used to form filters, they make it possible to obtain an extended bandwidth.
Different types of resonators that can be excited by an electrical signal are known and can be used to form such an array. For example, surface acoustic wave (SAW), bulk acoustic wave (BAW) and quartz crystal resonators are electromechanical resonators whose main drawbacks are their relatively large size and their off-chip implementation leading to connections that introduce spurious values and noise and that make them bulky.